Wolf kills not always obvious in livestock carcasses

Wolves chase cattle, running them to exhaustion, nipping at them and creating internal bruising.

By Heather Smith Thomas

For the Capital Press

Published on October 18, 2015 7:28AM

Courtesy of Sarah Swain
This young cow was run to exhaustion and injured internally by wolves. Experts say the only way to determine whether a cow or calf was killed by wolves is to skin the carcass and look for bruises and bite marks.

Courtesy of Casey Anderson
A young cow killed by wolves is skinned to show the bite marks. The cause of death often cannot be determined unless the carcass is skinned, experts say.

Couretsy of Sarah Swain
Phil Davis, who operates a ranch near Cascade, Idaho, lost several cattle to wolves before he realized the cause of death. Though they had no obvious injuries, bruising and bite marks under the skin revealed wolf depredation.

This summer Phil Davis lost several cattle to wolves, but they were not the typical victims of depredation.

Instead of having obvious bite marks on them, he found extensive bruising under the skin.

“If the animal is intact, most ranchers assume it died of something else (bloat, larkspur or disease) and don’t bother to skin it to discover bruising under the skin,” said Davis, who ranches near Cascade, Idaho. “Often the cattle killed in our area in late summer are left intact.”

The bruising is from adult wolves that are teaching their pups how to kill. They chase cattle, running them to exhaustion, nipping at them and creating internal bruising.

“These animals generally die, and people don’t know the reason. Ranchers don’t investigate whether it was a wolf kill,” Davis said. “I would have been able to collect compensation for more of my losses if I’d known what to look for.”

A neighbor had 10 cows and 5 calves killed, and buried them, Davis said. He then dug up the last one to get it confirmed as a wolf kill. He wished he’d have known what to look for before he buried them, Davis said.

In Idaho, compensation is paid for livestock killed by wolves, but it must be confirmed by USDA Wildlife Services.

“If we can confirm it, then it qualifies for compensation,” said Todd Grimm, Idaho state director of USDA Wildlife Services in Boise.

Some kills are obvious, with the animals ripped open and partly eaten, but others are more difficult to tell, especially if there are no outward marks of violence. Unless the animal is skinned to reveal bruising and bite marks under the skin, the rancher assumes the animal died of some other cause, he said.

“With cattle, as many as one-third of the deaths from wolves that we’ve confirmed have died in this manner. They are not outwardly obvious. We see more of this problem in summer (when packs have pups) than winter,” Grimm said.

“If Idaho or Montana ranchers think they have wolf depredation, they need to contact Wildlife Services and have us examine the carcass,” he said.

In Oregon the state conducts its own investigations, through the state Department of Fish and Wildlife. In Washington, ranchers should contact that state’s Department of Fish and Wildlife.

Washington officials have seen only one such confirmed case, said Donny Martorello, wolf policy lead for WDFW.

“We found one dead animal intact, where wolves had been killing calves and other livestock. Then the rancher found an adult cow dead, with no outward signs — except scratches behind the front legs,” he said.

“When wolves are running alongside the animal trying to bite the armpits, the skin sometimes isn’t broken; it looked like the teeth were just raking the skin. That cow had scrape marks at the armpits so we skinned the hide away, and underneath you could see the signs of biting; the wolves had turned the muscle into hamburger — all bruised and bleeding,” Martorello said.

“Only one carcass so far has fit into this category, but we may discover more — as ranchers learn what to look for, and call us,” he said. “Any time we get a report of depredation, we treat it as a crime scene, to find as much evidence as possible. But we have to get that phone call first.”

Russ Morgan, wolf coordinator for the Oregon Department of Fish and Wildlife, said wolves do kill animals this way, but added that it’s not really related to the age of pups or time of year.

“This is how wolves kill — with multiple bite trauma — chasing and biting and harassing the animal until it is exhausted, becomes weak or goes into shock, and is more easily killed,” he said.

“If you are going to identify what happened when you find a dead animal, to know whether it was a wolf kill, skinning the carcass is very important. In Oregon, any time there is a carcass found, even if it has been mostly eaten, we try to skin what’s left,” Morgan said.

“Wolves have relatively blunt teeth. They don’t always break the skin. You might not notice anything since cattle (or sheep) have long hair,” he said.

“In Oregon we have seen this a number of times — with both cattle and sheep — where you find the carcass intact, but with wolf tracks around it. We peel back the hide on those, and then the bites or bruising is clearly obvious.”

In Idaho, wolf compensation is handled through the Idaho Office of Species Conservation. Jon Beals heads the compensation program.

“If you are a rancher who has suffered a loss, and have the confirmed report from Wildlife Services, you’d contact me at the end of the grazing season, usually in November,” Beals said.

“If you have multiple losses, we process them as a group for the year. In years past, we had more claims than funding, so compensation rates were 45 to 50 percent of market value of the animal.”

He said that during the last few years, fewer claims have been made, so compensation rates have been closer to actual value.

“This year Idaho received $100,000 for use in compensation” from the federal government, he said.